webweaver

A week ago my 35,000 miles 2015 Macan Turbo threw a lot of yellow error codes on the main console: ECU failure, all-wheel-drive failure, traction control failure. The car was very sluggish when leaving from a standstill. At the time the errors happened I had driven the car for the first time that day, and I was maybe 1 mile from home. I was able to turn around and get back home. The following morning the engine ran as nothing had happened. Prior to this incident the car has been running just fine, with no indication of the problem.

In case it matters, I drive the car mostly during the winter. The car has snow tires on it, and I drive it in Tahoe, CA pretty much all winter long. This is the third winter the car spent a considerable amount of time in the mountains (around 7000 ft elevation).

I took it to my local dealer who was not able to replicate the problem. They said the error codes indicated over OBD II were P0300, P0304, P0305 and P0306, which are misfires on cylinders 4, 5, and 6, all of them on bank 2. There's no other indication of what might be causing the problem, so they don't know what to do. Their "solution" is to give me back the car so I can continue driving until a more conclusive error is reported by the computer. I have a problem with this approach for obvious reasons; more stuff can be damaged in the process, plus knowing the car can misbehave at any time, does not give me the peace of mind to rely on it for longer trips.

Any thoughts on what could be causing this issue?

PTEC

This is pretty standard fare for an intermittent electrical problem like that. They cant just throw a truckload of parts at it and hope it doesn't come back. It just doesn't work like that. I wouldn't worry about more damage possibly happening and even on the remote chance of it actually happening warranty would cover any additional damage.

webweaver

Given that it affects the whole of bank 2, could it be something that controls the whole bank? A cable or a control system of some sort?

Sorry, I'm having a hard time finding a diagram of the components around the engine so I'm just throwing out some ideas.

cviles

I agree it looks like a low-voltage gremlin somewhere but I'm not familiar enough with the wiring looms on the Macan to know if all the faults being on the same cylinder bank is significant. It's tempting to think it is. I think the more important detail is this seems to be the first drive after a period of hibernation if I read your post correctly? If there is a true mechanical problem or electrical corrosion issue it should reappear often and soon. If it's a battery problem I'm thinking it will only appear after a week or so of inactivity. If it doesn't come back, it's a storage issue.

My amateur opinion is: Drive it normally for a while. If it doesn't come back, look at tending to the battery. If it does, look for problems with wiring -- corrosion, loose connectors, etc.

But I don't work on Porsches for a living and I didn't stay at a Holiday Inn last night.

webweaver

The car has been driven before the mishap last Wednesday. Winter is not over yet, at least not up in the mountains in Tahoe

IMO if the battery is the culprit, one would see issues at ignition time. But I don't see any such issues. The problem appeared after the engine had been running for 5-10 minutes, enough for me to get about 1 mile from home.

I'll drive it for a while in the hope that the issue will appear sooner rather than later.

Petza914

When you left the car for a week, did you leave it locked or unlocked and on a battery maintainer or not? Locking Porsches puts all the subsystems to sleep, otherwise there's a higher than you'd like battery drain that occurs and I'm guessing g this was a low voltage issue. If you won't be driving the car for a week or longer, I'd recommend purchasing a battery maintenance device. The Porsche charger is actually made by CTek and you can buy the same one from Amazon without the Porsche logo on it for quite a but less. It simply plugs onto one of the lighter sockets ,but gas to be one with constant power or just install a quick disconnect pigtsil to the battery terminals. Porsches will frequently start just fine but then throw random codes with batteries that are slightly below full charge.

Alternatively, since all the misfires were on one bank, it might be something specific to that side, like a MAF if there is one for each side, a vacuum leak on the intake on that side, or possibly a faulty O2 sensor, but with the last, you'd usually get an O2 specific code not a general misfire.

webweaver

Good to know. I always lock my car, so battery drain should not be a problem. Ignition always seems to start right away, with no hesitation.

Wouldn't faults in the mass air flow and oxygen sensors be caught by the computer and shown as error codes? Same for the vacuum leak? The car did not show any other error code, which is puzzling.

Petza914

Yes, usually you'd get a code that says "X out of range" or "X limit reached" if unmetered air or an incorrect mixture that the DME can't compensate for occurs. I think you might just have to drive it and see if it recurs and if so, maybe there will be some new or different codes to help troubleshoot it.